DeepSeek can return a polished city forecast that conflicts with already-computed stale-observation, observed-break, or peak-window evidence. The completion path now carries the deterministic fallback guard state and overwrites only the critical fields when provider text or numbers contradict those local facts.
Constraint: Airport-read latency optimization keeps provider output narrow, so backend completion remains the authority for final highs and evidence conflicts.
Rejected: Trust provider final wording when present | it can reintroduce stale METAR anchors or miss observed high breaks.
Confidence: high
Scope-risk: narrow
Tested: pytest tests/test_web_observability.py -q
Tested: npm run build
2569718930@qq.com
0c9b07faaf